<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>houdunren.com</title>
  </head>
  <body></body>
  <script>
    let hd = "houdunren.com";
    let a = "u";
    // console.log(/u/.test(hd));
    console.log(eval(`/${a}/`).test(hd));
  </script>
</html>
